Hydraulic fluid power systems are used to operate a variety of machinery. Hydraulic systems transmit and control power for operating machinery by forcing water, oil, or other liquid under pressure through an enclosed circuit of fluid conducting lines. Quick-action couplings are used to quickly join or separate fluid conducting lines without the use of tools or special equipment.
The American National Standards Institute has published standard dimensions and requirements for Hydraulic Fluid Power--Quick-action Couplings in ANSI/B93.113M-1987. The ANSI Standard sets forth the interface dimensions and specifies basic performance requirements for two series of general-purpose hydraulic quick-action couplings, Series "A" and Series "B". Both series are in widespread use and have similar technological advantages. The International Standards Organization has also published the same standard dimensions and requirements for Series A and Series B couplings under the same title in ISO 7241. Couplings and coupling components made by various manufacturers in accordance with the Standards are interchangeable.
Quick-action couplings made according to the Standards comprise two primary components, or members: a generally cylindrical socket having an axial fluid flow passage that is attached to one hydraulic line and a generally cylindrical plug also having an axial fluid flow passage that is attached to the other. The plug is inserted into the socket to join the two lines and to create a single fluid flow passage between the lines.
Generally speaking, the socket has a plurality of evenly spaced locking balls contained in apertures that form a circle around the plug receiving end of the socket. A spring biased detent sleeve circumscribing the socket holds the locking balls radially inwardly. To insert the plug into the socket, the operator first uses one hand to pull the detent sleeve longitudinally away from the plug receiving end of the socket so that the balls are released. Using the other hand, the operator inserts the plug into the socket. The plug has an annular groove to receive the locking balls. The operator then releases the detent sleeve, which holds the balls in the annular groove in the plug and secures the plug in the socket. The operator removes the plug from the socket in an analogous fashion.
The interchangeable couplings described above have several disadvantages that detract from their usefulness. For example, the operator pulls the sleeve against the bias of a spring so that the plug can be inserted into and withdrawn from the socket. Machinery operators sometimes wear heavy rubber gloves that become oily in use and reduce the dexterity with which the sleeve can be manipulated. The coupling also requires the operator to use both hands to insert the plug into the socket. Using both hands reduces the speed with which the socket and plug can be connected and disconnected.
These disadvantages have caused problems in the operation of rescue equipment that is hydraulically powered, and, in particular, the operation of a rescue tool that is used for extracting victims from automobile wreckage. One such rescue tool is manufactured by Hurst Performance, Inc. under the trademark JAWS OF LIFE.RTM.. The JAWS OF LIFE.RTM. rescue tool uses two couplings to form a circuit, one in a hydraulic line transferring pressurized fluid from the power source to the tool and one in a return hydraulic line leading from the tool back to the power source. Difficulty has been encountered by the rescue operator in connecting and disconnecting the hydraulic lines at the couplings.
The couplings are generally oriented in different directions and are connected and disconnected one at a time. The rescuer uses both hands to connect each coupling. The rescuer pushes the sleeve longitudinally to release the retaining balls so that the plug can be inserted into the socket and secured and so that the plug can be withdrawn. Frequently, the rescue operator must take off his gloves to connect or disconnect the coupling, consuming even more time in critical moments.
The performance of rescue equipment depends in part upon its compatibility with the power source and in part upon the speed with which the equipment can be used. Coupling components should be manufactured in accordance with ISO 7241 for interchangeability so that the rescue equipment can be used with any available power source without having to change any of the coupling components, either in the hydraulic lines attached to the tool or in the hydraulic lines attached to the power source. The coupling components should also be easily and quickly connected and disconnected by the rescuer.
Snap couplings adapted for assembly and disassembly with one hand have been available in the past, but these couplings are not interchangeable with standard components and are not suitable for use in rescue equipment. For example, U.S. Pat. No. Re. 23,120 to C. E. Earle et al. and U.S. Pat. No. 2,377,812 to A. T. Scheiwer disclose such snap couplings. These patents both disclose a spring-biased detent-actuating sleeve carried by a socket. The mating plug engages a detent operator, or plunger, to bias the sleeve to actuate the detent. As viewed with the socket on the left, the springs are located entirely or at least partially to the right of the ball detents, which requires the socket to have a length to accommodate the spring and requires the plug to have a length to accommodate the distance between the ball detent and the plug receiving end of the socket. Such a coupling is not interchangeable with Standard components made according to ISO 7241, which do not provide the required length in the socket or plug.
It would be desirable to provide interchangeable couplings for use with hydraulically powered rescue equipment such as the JAWS OF LIFE.RTM. rescue tool that are easily and quickly connected and disconnected by the rescuer. In particular, it would be desirable to provide a coupling that could be quickly and easily connected and disconnected with one hand while capable of withstanding the rigors of heavy use encountered in rescue operations, and at the same time being interchangeable with standardized components presently in use.
The present invention provides a quick-action fluid coupling having interchangeable components that can be connected and disconnected with one hand and can withstand the rigors of use with rescue equipment. The coupling components of the present invention are fully usable with coupling components presently in use that are manufactured according to the Standards, and do not require the replacement of existing components for compatibility of rescue equipment and power source. The present invention also provides a coupling assembly for connecting and disconnecting two couplings simultaneously, even further decreasing the time required to perform a rescue operation.